With the development of the smart terminals, the product of unifying the display screen and the touch screen (generally in the name of touch control screen) has become more and more popular. For achieving display and touch control on the same screen. As shown in FIG. 1, the time division multiplexing method is commonly utilized in prior art. In one frame, the scan to the image signal is accomplished, and then the scan to the touch signal is finished. For instance, the time period of one frame is 16 milliseconds, wherein the previous 12 milliseconds is employed to scan the image signal, and the latter 4 milliseconds is employed to scan the touch signal. However, at the each initial moment of scanning the touch signal, the present capacitance signal has to be acquired. The later judgment of the touch signal is based on this present capacitance signal. Thus, in the aforesaid time division multiplexing method, if the present capacitance signal is influenced by the environment, the judgment of the later touch signal will be incorrect.